System of electrical distribution.



I 1 PATENI'ED NOV. 5, 1907. I. L. WOODBRIDGE.

SYSTEM OF ELECTRICAL DISTRIBUTION. APPLIOAIIOH FILED n! 21, 1901.

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UNITED STATES PATENT OFFICE.

.TOSEPH LESTER WOODBRIDGE, OF PHILADELPHIA, PENNSYLYQNIA.

SYSTEM OF ELECTRICAL DISTRIBUTION.

Specification ofi Letters Patent.

Patented Nov. 5, 1907.

Application. filed May 21.1907- Seriai No. 374,943-

'Pennsylvania, have invented a certainnew'and useful System of Electrical Distribution, of which the {ollowing is a specification.

My invention relates to those systemsof electrical distribution in which there is an alternating pjurent and a direct current circuit with means for transferring energy in either direction between the two,- and it is the object of my invention tolprovide more sensitive means for automatically effecting such transfer and for controlling the power factor on the alternating current circuit.

The general natiirc and scope of my invention will be more fully understoodby reference to the following description in connection with the accompanying drawing in which is diagrammatically illustrated a system of distribution embodying features of-iny invention.

A, is a source of three phase alternatingcurrent fceding the consumption circuit 1, 2, 3, which supplies current to the translating devices L.

C. is a storage battery connected in series with its booster B, across the direct current terminals of the synchronous converter R. by means of the conductors 25 and 2G. The converter R, is connected on the alters nating current side by means of the conductors 27. 28 and 29, to the alternating current circuit 1, 2, and 3. The field F, or the booster B, is controlled by the exciter E, which will now be described.

.. l d The excitcr E consists of a stationary field frame M,

" and a rotating armature D, which latter is directly connected by means of the shaft H, to the synchronous motor S. The motor S, is driven in synchronism with the electro-motive-force of the source A, by current supplied by conductors 14, 15 and 16. This motor, as shown, is of the revolving field type, its field current being taken from the terminals of theconverte'; R. by means of the conductors 58 and 59. The armature D. is provided with a bi-polar winding, and .is supplied with alternating current taken irom the secondaries of the series transformers T, T, and T Whose primaries are connected in series with the alternating current circuit 1, 2, The secondaries of these series transformers are connected by means of conductors 30, 31, 32, 33, 34, and 35, to sixcquidistant points 4, 5, (3, 7, 8, and'59, in the winding of the armature D,

with our pole pieces P1 5 P and F The com- I mutator G, is'provided with two sets of brushes. One

pair of these-brushes lll'and 11, is connected by means of the co'nductors 23, and 24, directly across the terminals of the battery C. The other pair of ln'ushes 12 and 13, is'connectcd by means of the conductors 21 and 22 to tlreterminals of the field F, of the booster B.

In this latter circuit is also connected in series the field winding l7, 18, 19, and 20, of the exciter E. A shuntficld winding 60, 61, 62;. and 63, is also shown on the polcs'of the exciter E, connected across thedirect current terminals of the convcrter R. A switch I, is inserted'in this field circuit, for reversing its polarity and a rheostat Q, for controlling its effect in the usual manner. The field coils 60, 61, 62, and 63, arcwound in such direction as to produce a field excitation in of the arrow K. The operation of this apparatus" is as follows:

The current supplied by the secondary windings of theseries transformers T T and T to thearrnature D would, if the armature were stationary, produce a rotating magnetic field. The armature, however, is driven by the motor S, in .the opposite direction to the rotation of the field and at the same speed, the

result being that a stationary field is produced by this alternating current. The adjustment is such that this field assumes the direction of the arrow K, so that the poles P and P, are both of the same polarity, that is, north polarity, while the poles P and P are both of south polarity. The inductive effect of the field wK, will be .to produce a direct current voltage across the brushes l0 and 11, which are at right angles to the axis of the field. When the load on the alternating current circuit 1, 2, 3, due to the translating devices L,is exactly equal to the desired output from the source A, the adjustment is such that the voltage produced across the brushes 10 and 11, by the combined effect of the alternating current excitation and .current in the booster field winding F. The adjustment between the battery C and the converter R, will then be such that the battery is neither charging nor discharging, and the'converter R, is neither taking energy from, nor delivering energy to the alternating current circuit 1, 2, and 3. If now the load on the circuit 1, 2, 3, should increase, a small proportion of this increase getting back to the source A, through the transformers T T and T, will produce an increase in the current transmitted from the sccondary windings of these transformers to the armature D, thus producing an increase in the field strength due to this exciting current and a corresponding increase in the v 'potentiall between the brushes and [O wingt'o the low resistanceof thewinding of the armature D and' of the storage batteryfl, a comparatively-small.

. increase of potential across the'brushes 10 and ra sin;

produce a considerable flow offcurrent hetween these brushes and'theibattery'. This current will produce an auxiliary magnetic .fieldin the 'exciter E, in the direction of the arrow K, and this auxiliary field will i in turn'produce azdifferenceof potential between the brushes 13, thus causing a flow of current from these brushes through the field winding of the exciter 17, 18 19 and 20, and the field winding F, of the booster B.. This current-in the booster field F, .will excite the booster in theproper 'directionto cause the'battery 'to discharge into the converter R, causing the latter to deliver energy to the circuit 1, 2, 3, and relieve ,the

f source A, of the greater portion of the increase of load:

I of direct current electro-rnotive-iorcel' Conversely, if the load on the circuit '1, 2, 3, should decrease, the field strength K, produced by the alternating current in the armature D, will decrease, and

the voltage across the brushes 10 and .11, -will.decrease correspondingly, causing current to flow from the battery into the armature D. This'current will produce an auxiliary field in line'with the arrow- K but in the opposite direction, thus producing a reversal of current in the booster field F'and causing the battery to charge from the converter R, which in tumwill I take energy from the circuit 1,2, 3, thefiby maintaining the load on the source A. The effect of the current from the brushes l2. and 13, in the armature D, of

the exciter will be -to' oppose the increase in field strength produced by the increase in alternating current from the transformers T, T and T The effect of this current from the brushes 12 and 13, in the field windings 17, 18. 19 and 20, will, however, be such as to assist the excitation produced by the alternating current. The number of turns of the winding 17 '18,

19 and 20, may be so adjusted that the effect of current v in this winding from the brushes 12 and 13, will nearly counterbalance the effect of the same current in the armature winding. The advantage of the winding 17, 18, 19 and 20, is therefore to permit a much greater current to flow through the booster field F, with-.a

given increase of load on the circuit 1, 2, 3, than would erate with the increase in excitation in thearmature A, caused byv an increase in load on the circuit 1, 2, 3, and will assist in producing a flow of current from the brushes 10 and 11, into the battery. IEwill be understood, however, that the brushes 10 and '1ljn1ay be connected across'any approximately constantslihrae The effect of the applicationto the direct current terminals of the converter R, of the variable potential necessary to vary or reverse'the transfer of energy eroded v bet'w'eii ashame current circuit and the'battery produce avariation in the power factor of the converter and introduce wattless' currents into the I I alternating current --circuit which may be su'fiicient to "cause undesirable results. In order to counteract this effect a second e'xciter' E -is shown driven by the same synchronous motor-S, the armature D, of'this exciter motor. A second set ofseries transformers T, T and T, is shown with their primary'windings connected in series with the alternating current-conductors 1, 2, and 3, andtheir secondaries connected by diametrical sixphase connection to the armature D, by the con-.

ductors as, 31,, as, as, 40 and; 41, in the same manner as.

was described in 'connecti on with the armatureD, of the exciterE. 'The'efiec't of the alternating current from the transformers T, T and T, on the armature D is such as would produce a magnetic field-in the direction of the arrow K, this field being held, station-' excitation due to this alternating current in the arms ary in position by the rotation of the armature. The

ture is, however, neutralized by a shunt field winding .being'mounted uponthe shaft-H, of the synchronous 1 49, 5Q, 51 and 52,which is connected across the direct current terminals of the converter R, by means of the conductors 42 and.43. A-rheostat Q, is introduced in 'series with this field winding to adjust its strength.

A commutator G, is connected to the armature wind ing of- D, and bearing on this commutator are two I pair of brushes 45-46 and 4748. The brushes 45 811th 46, are electrically connected by a conductor 57 of low resistance; that is, they are short circuited. The other pair of brushes 47.and 48'is connected in series between conductor 42, which is connected to one of the direct current terminalsof the converter R, and the shunt field winding U, of this converter, this shunt field winding being connected at its other terminal to the opposite direct current terminal of the ponverter.

Connected in series between the brush 48 of the exciter E and the fildwinding U, of the converter i is a series winding53, 54, 55, and 56, on the fields of the exciterE, which serves to counteract the armature re-action in 'the'armature D, due to the current flowing betweenthe brushes 47 and 48., The operation of this exciter E is then as follovlrsi-So long as the alternating current'in circuit 1, 2, 3, remains constant'in amount and phase relation the adjustment is such that there is no field excitation in the exciter E, andno voltage across either pair of brushes. The current for the field U, of the converter 3, flows from conductor 42, through the armature D, from brush 47 to brush 48 and thence around the series winding 53 54, 55, and 56, this latter field winding counteracting the effect which would otherwisebe produced on the field strength by the ampere turns of; this current in the armature. If, however, the phase relation of the current in the. circuit, 1, 2, 3, should change, a component at right angles to the original phase position of thecurrent would be introduced. which; would produce a magnetic field in the-exciter E, inithe direction of arrow, K. This field will pioduce' a'voltageacross the brushes 45 and 4dand because$i the-low4esistancemf the conductor 57, a. very considerable current will fihw between these brushes. This latter currentwill produce a considerable field strength in'gthe direction of the arrow K, and this. field will produce an el i ffl fi q across thebrushes 47 and 48/ The adjustment should be such that when a lagging component oi, current is introduced into the circuit 1, 2, 3, the resulting electromotive-force across the brushes 4? and 48 will be such as to increase the current through the field winding U of the converter B. This increase in field strength of the converter R by introducing leading currents into the circuit 1, 2, 3, in the manner well known in the art, will counteract the effect of the lagging component, limiting this latter component to the ver j small amount necessary to produce the effect just described in the exciter D. Should a leading component be introduced into the circuit 1, 2, 3, the effect on the excitcr IE, will be just the reverse and the voltage developed 1 across the brushes 47 and 48 will be such as to reduce the current in the field winding U and thus counteract such leading component. If the amount of current in the circuit 1, 2, 3, should increase without any change in thephase relation, the effect of this-current would not be entirely neutralized by the shunt field.

force across the brushes 47 and 48.

I winding 49, 50, 51 and 52, (assuming no change in the position of the rhcostat Q and the effect of this increase would be to establish a field in the direction of the arrow K, which would produce an electro-motive' The effect of this electro-motive-force, would he to change thecurrent in the field U of the converter R and introduce-wattless components into the circuit 1, 2, 3. A very small wattless component, however, by producing a mag- 3 net-ic field in the direction of the arrow K and a corresponding current through the conductorffi would immediately counteract the effect of the increase in the amount of current in the circuit 1, 2, 3. The coil:- bination therefore of the two exciters E and E, driven by the synchronous motor S and excited by current virom the alternating current circuit 1, 2, .3, in comhination-with the field windings above described constitutes an automatic control of the transfer of energy between the alternating circuit 1, 2, 3, and the battery 0.

It will be understood that the exact value of the potential difference maintained across the brushes 1011 in exciter E and across the brushes i5 and 46 in exciter E is immaterial in as much as the shunt field windings on the two excitcrs may be designed with reference to any value of this potential difference that may be selected. In referring to a potential difference whose value may be arbitrarily selected, it will also be understood that zero is one of the valucs 50 which. such potential difference may assumc, corrcsporrding to a short-circuit as shown in connection with exciterE.

What I claim is:

-1. In combination an armature provided with winding and commutator, a magnetic field sti-ueture in inductive relation to the armature and adapted to 'compiete thei magnetic circuit for two sets of magnetic lines through-f the armature, each corresponding in number or? poies, with the armature winding but unguhirly displaccd uithhe' spect to the other; two sets of brushes bearingv on the commutator,:i'conducting circuit connectingitbe .op site brushes of one set and including a compcnsutingpmdirig on the iicld structure and an external regulating coil, a

conducting circuit connecting the other pair of brushes,

means for producing relative rotation of armature and field structure. and means for supplying exciting current to tin.= Piiilillfiii'e winding.

I 2. In combination an armature provided with winding l and commutator, a magnetic field structure in inductive relation to the armature and adapted to complete the magnetic circuit for two sets of magnetic lines through the armature, each corresponding in number of poles with the armature winding but angulariy displaced with respect to the other; two sets or brushes bearing on the commutator. a conducting circuit connecting the opposite brushes oi. one set and including a compensating winding on the field structure, a conducting circuit connecting the other pair of brushes. means for producing relative rotation of armature and held structure; and means for suppiyi'ngmxciting current to the armature winding.

3, 1n combination, an alternating current circuit and its source, a dynamo electric machine comprising armature and magnetic field structure relativ'ely rotatable; means for supplyingto the armature alternating currents corresponding in phase relation and proportional to those, in the circuit; means for producing relative rotation of armature and field in synchronism with the source;-a commutator connected to the armature; two sets of bruahesfor the commutator, anguiariy displaced with mined potential across the opposite brushes or one set; a regulating coil connected across the opposite brushes 0! the other set; and a winding on the magnetic field connected in series-with the r-regulating coil and adapted to compensate forj the armature reaction produced by the current from said .brushes.

4, In combination, an alternating current circuit and its source, a dynamo electric machine comprising arma .ture and magnetic field structure relatively rotatable; means for supplying to the armature alternating currents corresponding in phase relation and proportional to those in the circuit; meansfor producing relative rotation of armature an'd'field in synchronism with the source: a commutator connected to thearmature: two sets of brushes for the commutator angularly displaced with respect, to each other, means for maintaining across the opposite brushes of one set a potential independentot the field excitation, a regulating coil connected across the opposite brushes ot the other set; and a winding on the magnetic field connected in series with the regulating coil and adapted to compensate for the armature reaction produced by the current trom'said brushes.

5. In combination. an alternating current circuit and its source, a dynamo electric machine comprising armature and magnetic fieldlstructure relatively rotatable; means for supplying to the armature alternating currents corresponding in phase relation 'and proportional to those in the circuit; means for producing relative rotation of armature and field in synchronism with the source a commutator connected to the armature; two sets of brushes for the ,commutator angularly'displaced with respect to each other; means for maintaining a predetermined potential across the opposite brushes of one set: in regulating coil connected across the opposite brushes of the other set: and a winding on the magnetic field adapted to compensate for the armature reaction produced by the current from said brushes.

its source, a dynamo electric machine comprising armature and magnetic field structure relatively rotatable, means for supplying to the armature alternating currents; corresponding in phase relation and proportional to' those in 'tlieclrcult; means for producing relative rotation of armature and field in synchronisrn with the source; a commutator connected to the armature; two sets oi brushes for the commutator angularly displaced with respect to each other; means for maintaining across the opposite. brushes 0! one set a potential independent or thefield excitation; a regulating coil connected across the'opposite'brushes of the other set; and a winding on this magneticfleld adapted to compensate for the armature ractionproduced the current from said brushes.

7. In combination ran-alternating current circuit and its source; a lironous dynamo electric machine connected to the alternating current circuit and provided with a regulating coil adapted to control the transfer 0! watt less currents between the machine and the alternating respect to each other; means for maintaining a predeter-- (3. In combination, an alternating current clrcuit and the regulating coil'; a winding on the held of the exciter vas through the armature winding alternating currents corv currents between the machine and the' i' dinect'eurrent c'ircult; an exciter' for the regulating'eoif cgm rising a mag the regulating coil and adapted to compensate for the "its source; a synchronous dynamo-electric machine conacross one set of brushes; electric'al connect ion s from the magnetic fleld and an armature .provided with a winding current circuit; an exciter tor the regulating coil comprising a magnetic held and an armature'provided with a winding and commutator; means for transmitting responding in phase and proportional to those in the alternating current circuit; two sets of brushes bearing upon the commutator and angularly displaced wit h respect to each other; means for maintaining a predetermined potential across one set of brushes; electrical connections from the secondset to the regulating coll a winding on the field 0; the exciter connected in series between the second set of brushes'and the regulating coil and adapted to compensate tor the armature reaction due to the current from said brushes; and means for producing relative rotation between the held and armature of the exciter in synchronism with the alternating'current source.

8. In combination anlalternating current circuit and its source, a synchronous dynamo-electric machineconnected to the alternating current circuit and prolvided with a regulating coil adapted to control the transter of wattless 'netlc field and an armature provlded wiih a. grinding and, commutator; means for transmittingfthrouglr the arma ture winding alternatingcurrents corresponding in phase and proportional to .those in the aiternat ingfcurrent 'circult; two sets of brushesbearing upon the commutator and angularlyldispiaced with respect to'eachpther; a con-' ducting circuit oi! low resistance connectediacross one set or brushes; electrical connections from the second set to connected in series between the second .set of brushes and armature reaction due to the current from said brushes; and means, for producing relative rotation between the field and armature ot the exclter in synchronism with the alternating current source. I

9. In combination an alternating current circuit and nected to the alternating current, circuit and provided with a regulating coil adapted to control the transfer of wattless currents between the machine and the alternating current dlnchit; an exciter tor the regulating coil comprising a magnetic held and an-armature provided with a winding and commutator; means for transmitting through the armature winding alternating currents'correspond i11gin phase and proportional to those in the alternating current circuit; two sets 01! brushes bearing upon-the commutator and angularly displaced with respect 30 ,ea'ch other; means for maintaining a predetermihedpoentiai second set to the regulating coil, and means for producing relative rotation between the iield and armature or the exciter in synchronism with the alternating current source.

10. In combination an alternatingcurrentfcircuit and nected to the alternating circuit and provided with a'regulating coil adapted to control the -transfer of wattless currents between the machine and the alternating current circuit; an exciter for the regulating ,coil comprising a a'ndcommutator; means for transmitting through the armature winding alternating currents corresponding in phase andpro rtional to those in the alternating currentcircuit; two 'sets or brushes bearing upon the commutator and singularly isplaced with respectto each other,' a con ducting clrcui aotlow resistance connected across one set. or brushes electrical connections from the second set to the regulatingcoil; and means for-.1 producing relative rotation between the field and armature of the exciter in syuchronism with the alternating-current source.

its source, a rains connected between the alternating current circuit ably transfer energy from one to the other; a regulating citeifor said regulating .coil comprising ama'gnetic flelil' "and an-armature provided with a winding and commutator; means for: transmitting through the armature winding alternating current-corresponding in phase and proportionaltojthose in the'aitcrnatinglcurrent circuit; two sets of brushes bearing upon the commutator,- angu larly displaced with respect to each other,- means for maintaining a predetermined potential across one set; electrical connections between the second set and the "regulating coil; a winding on the field of the exciter 'c'onn'ected in-series between the second set and the regulatiug coil and adapted to compensate for the armature freaction due to the current fromthe second set of brushes; and-means'tor producing relative rotation between the -field and'armature of the exciter in. synchro- {nism with the alternating current source.

' .12. In combination, an alternating current circuit and its source, direct current source, transforming apparatus connected between the alternating current circuit and the direct current source, and adapted to interchangeablytransfet 'energy from one to the other; a regulating coil adapted to control said transfer of energy; an exalter for said' regulating coil comprising a magnetic field and an armature provided with a winding and commutator; I means for transmitting through the armature winding alternating currents corresponding in phase and proportional to those in'the alternating current circuit; two sets'ot'brushes,bearing upon the commutator angularly displaced with respect to each other; means for maintaining a predetermined potential across one set; electrical connections btweerrthe second set and the tion "between the field a'nd armature of the exciter insyncln'onism with the alternating current source.

13. in combination an alternating current circuit and its source; a direct current source; transforming apparatua connected between the alternating current circuit and the direct current source and adapted to interchangeably transfer energy from one to the other; one regulating coll adapted to control said transfer of energy;

of \ynttless currents between the transforming appa rutus and the alternating current circuit; an exciter for each ,.1'egul:\ting coil each exciter comprising a magnetic fieid and an armature provided with a winding and commutator; means for transmitting through the armature winding of each exciter alternating currents correspondn lug in phase and proportional to those in the alternating current circuit; two sets of brushes for each exciter, bearing upon its'commutator and angular-1y displaced, with respect to each other; means for maintaining a predetermined potential across one set of brushes (in each exciter, electrical connections from'the-second set of brushes on each exciter to the'corresponding regulating coil of the transforming apparatus, a winding on the field of each exciter connected in series between the second set of brushes and the corresponding regulating coil of the transformingapparatus, and adapted to com-,

sald brushes; and means for producing relatire rotation between the held and armatdre of each exciter in synchronlsrn with the alternating source.

In testimony whereof I have hereunto signed my nan: JOSEPH LESTER WOODBRIDGE. Witnessesi I Frans: E. Farmed,

- 11. In combination, an alternating current circuit and A. B. S'rouon'roN.

and the directcurrent source and adapted to interch'angedirect current source, transforming appacoil adapted to control said transtenof energy; an ex--- rgulating'coil, and means for producing relative rotaa-second regulating coll adapted to control the transfer peusate tor the armature reaction due to the current from 

